Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
1. A growth layer in secondary xylem seen in a cross section of a woody stem or branch.
2. A layer of calcareous material or other substance deposited in a single period of growth of an animal, as in an otolith or a turtle scute.
(Botany) another name for annual ring
A layer of wood formed in a plant during a single period of growth. Growth rings are visible as concentric circles of varying width when a tree is cut crosswise. They represent layers of cells produced by the tissue known as vascular cambium. ♦ Most growth rings reflect a full year's growth and are called annual rings. But abrupt changes in the environment, especially in the availability of water, can cause a plant to produce more than one growth ring in a year. See more at dendrochronology.